Heat exchanger fin and manufacturing method of the same

ABSTRACT

A heat dissipation device includes a base plate and a plurality of fins arranged on the base plate. Each fin includes a fin body including a first metal sheet and a second metal sheet coupled to each other, wherein the fin body is curved and includes a first portion and a second portion transverse to the first portion, an evaporation channel defined in the first portion, one or more connecting channels disposed in the first portion and in fluid communication with the evaporation channel, a condensation channel defined in the second portion, and one or more auxiliary channels disposed in the second portion and in fluid communication with the one or more connecting channels and the condensation channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of and claims benefit under35 U.S.C. § 120 of U.S. non-provisional application Ser. No. 17/147,182,filed Jan. 12, 2021, which claims priority to under 35 U.S.C. § 119 toU.S. provisional application Nos. 62/967,064, filed Jan. 29, 2020,62/970,731, filed Feb. 6, 2020, and 63/046,721, filed Jul. 1, 2020. Thisdivisional application also claims priority under 35 U.S.C. § 119 toTaiwanese Patent Application No. 109101118 filed Jan. 13, 2020, in theTaiwan Intellectual Property Office. The entire contents of theforegoing applications are hereby incorporated by reference.

TECHNICAL FIELD

Embodiments of the disclosure relate generally to the field of heattransfer and, more particularly, to heat exchanger fins andmanufacturing methods of the same.

BACKGROUND

During operation, electronic devices generate heat that must bedissipated quickly and efficiently to keep operating temperature withinmanufacturer recommended ranges in a range of operating conditions. Asthe electronic devices become more and more complex, the powerrequirements thereof increases and heat generated is increased. Thus,cooling requirements increase.

Several techniques have been developed for dissipating heat fromelectronic devices. One such technique is an air-cooling system, whereina heat exchanger is in thermal contact with the heat generating devicesfor transporting heat away from the devices, and air flowing over theheat exchanger cools the heat exchanger and thereby removes heat fromthe heat exchanger. One type of heat exchanger includes a plurality offins extending from a base plate. The plurality of fins increases therate of heat transfer via convection to the environment of the heatexchanger by increasing the surface area of a heat source in thermalcontact with the heat exchanger. Heat is transferred from the heatsource to the base plate, the base plate to the plurality of fins andthe environment, and the plurality of fins to the environment.

The heat transfer may be aided by a fan, blower, or any other devicethat increases air flow over the fins, or heat can be transferred bynatural heat loss due to convection. In natural convection, the heatedtemperature air is less dense than the surrounding air (environment) andrises from the heat exchanger and plurality of fins. For naturalconvection to be effective, the heat exchanger and orientation of theplurality of fins during operation are positioned in a direction thatwill not impede air movement. When positioned horizontally, theplurality of fins face upward, and when positioned vertically, theplurality of fins are oriented to allow higher temperature air to rise.

The thermal performance of the plurality of fins of the heat exchangersis dependent on heat transfer effectiveness. Thus, shape, thickness,material, and other structural enhancements contribute to the thermalperformance of the plurality of fins. One type of enhancement is aclosed-looped system, wherein a vacuum area carries heat from the heatsource by evaporation of a working fluid which is spread by a vapor flowfilling the vacuum. The vapor flow condenses over cooler surfaces, and,as a result, the heat is distributed from a heat source evaporationinterface surface to a larger condensation cooling surface area. Flowinstabilities occur inside the enhanced heat exchangers due to the heatinput at the heat source end and heat output at the cooling surface end.Thereafter, condensed fluid flows back to the evaporation surface.

When a closed-looped heat exchanger is positioned vertically, theplurality of fins are aligned such that higher temperature air can rise.However, the added weight of the closed-looped enhancement requirescostly attachments to couple the fins to the heat source and/ornon-standard attachment mechanisms. Also, due to the vertical alignment,heat transfer efficiency of the closed-looped enhancement decreasesalong the mounted surface of the heat exchanger the further the mountedsurface is away from ground due to the inefficiency of the working fluidto rise against gravity. Thus, the occurrence of dry-out is increased,causing the electronic devices to overheat, fail or be damaged. In someelectronic device that operate vertically (e.g., longitudinal dimensionis oriented vertical to the ground or base), there are more than onesource of heat and thus more than one heat source areas (on the heatexchanger) which will need cooling by the heat exchanger. Operatingtemperature allowance for relatively lower-powered electronic devices isless than that of relatively higher-powered electronic devices. Thelower-powered electronic devices may be positioned closer to ground(e.g. at a lower position) compared to the higher-powered electronicdevices due to rising of higher temperature air. For certain heatexchangers, improved heat dissipation efficiency is often observed inportions of the heat exchanger that are closer to ground, since theworking fluid accumulates there due to gravity.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1A is a schematic front elevation view of a heat exchanger,according to embodiments of the disclosure.

FIG. 1B is a schematic diagram of a right side view of a fin of the heatexchanger in FIG. 1A, according to embodiments of the disclosure.

FIG. 2A is a schematic diagram of a right side view of the fin of theheat exchanger of FIGS. 1A and FIG. 1B without the base plate, accordingto embodiments of the disclosure.

FIG. 2B is schematic diagram of a left side view of the heat exchangerfin in FIG. 2A, according to embodiments of the disclosure.

FIG. 3A is a schematic perspective view of a heat exchanger fin,according to embodiments of the disclosure.

FIG. 3B is a plan view of the heat exchanger fin of FIG. 3A, accordingto embodiments of the disclosure.

FIG. 4A is a schematic perspective view of a heat exchanger fin,according to embodiments of the disclosure.

FIG. 4B is a plan view of the heat exchanger fin of FIG. 4A, accordingto embodiments of the disclosure.

FIG. 5A is a perspective view of a heat exchanger fin, according toembodiments of the disclosure.

FIG. 5B is a plan view of the heat exchanger fin of FIG. 5A, accordingto embodiments of the disclosure.

FIG. 6 is a flow chart of a manufacturing method of heat exchanger fins,according to embodiments of the disclosure.

FIG. 7A is a perspective view of the heat exchanger fin of FIG. 1A andFIG. 1B following an operation of the manufacturing method of FIG. 6 ,according to embodiments of the disclosure.

FIG. 7B is a plan view of the heat exchanger fin of FIG. 7A following anoperation of the manufacturing method of FIG. 6 , according toembodiments of the disclosure.

FIG. 8 is a schematic perspective view of a heat exchanger, according toembodiments of the disclosure.

FIG. 9A is schematic perspective first view of a heat exchanger fin ofthe heat exchanger of FIG. 8 , according to embodiments of thedisclosure.

FIG. 9B is schematic perspective second view of the heat exchanger finof FIG. 9A, according to embodiments of the disclosure.

FIG. 10 is a partial cross-sectional view of the heat exchanger fin ofFIG. 9A along line B-B and between lines C-C and D-D of FIG. 9A,according to embodiments of the disclosure.

FIG. 11 is a flow chart illustrating a manufacturing method of the heatexchanger fin of FIG. 9A, according to embodiments of the disclosure.

FIG. 12A is a side view of a heat exchanger in the direction of arrow M,according to embodiments of the disclosure.

FIG. 12B is a schematic perspective of the heat exchanger in FIG. 12A,according to embodiments of the disclosure.

FIG. 13A is a side view of a heat exchanger fin of the heat exchanger ofFIG. 12A and FIG. 12B in the direction of arrow M in FIG. 12B, accordingto embodiments of the disclosure.

FIG. 13B is a schematic perspective view of the heat exchanger fin ofFIG. 13A, according to embodiments of the disclosure.

FIG. 13C is a side view of the heat exchanger fin of FIGS. 13A and 13Bin the direction of arrow N, according to embodiments of the disclosure.

FIG. 13D is a side view of the heat exchanger fin of FIGS. 13A and 13Bin the direction of arrow P, according to embodiments of the disclosure.

FIG. 14A is a schematic view of a first metal sheet of the heatexchanger fin of FIGS. 12A-13D, according to embodiments of thedisclosure.

FIG. 14B is a view of a second metal sheet of the heat exchanger fin ofFIGS. 12A-13D, according to embodiments of the disclosure.

FIG. 15 is a flow chart illustrating a manufacturing method of the heatexchanger fin of FIGS. 12A and 12B, according to embodiments of thedisclosure.

FIG. 16A is a schematic perspective view of the heat exchanger fin ofFIG. 12A and FIG. 12B following an operation of the manufacturing methodof FIG. 15 , according to embodiments of the disclosure.

FIG. 16B is schematic perspective view of the heat exchanger fin of FIG.16A following an operation of the manufacturing method of FIG. 15 ,according to embodiments of the disclosure.

FIG. 17 is schematic perspective first view of a heat exchanger,according to embodiments of the disclosure

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, and examples, for implementing different featuresof the disclosure. Specific embodiments or examples of components andarrangements are described below to simplify the present disclosure.These are, of course, merely examples and are not intended to belimiting. For example, dimensions of elements are not limited to thedisclosed range or values, but may depend upon process conditions and/ordesired properties of the device. Moreover, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed interposing the first and second features, suchthat the first and second features may not be in direct contact. Variousfeatures may be arbitrarily drawn in different scales for simplicity andclarity.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The device may be otherwise oriented (rotated 90 degrees orat other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. In addition, the term“made of” may mean either “comprising” or “consisting of.”

Embodiments of the disclosure are directed to heat exchangers and heatexchanger fins, and having a working fluid under vacuum therein, andmanufacturing methods of the heat exchanger fins. In an embodiment, aheat exchanger includes a plurality of heat exchanger fins and a baseplate. Each heat exchanger fin comprises an exchanger enhancement havingchannels therein. The channels are formed by first and second metalsheets. The channels are under vacuum and have a working fluid therein.The channels decrease the volume of working fluid and facilitates thecreation of non-equilibrium pressure conditions, strengtheningself-sustaining turbulent driving forces within each heat exchanger finfor heat dissipation. The channels (or a portion thereof) of the heatexchangers, according to embodiment of the disclosure, provide improvedefficiency in dissipating heat from both low-power, low operatingtemperature heat sources and from high-power, high operating temperatureheat sources. The low-power, low operating temperature heat sources andthe high-power, high operating temperature heat sources are positionedvertically separated from each other, wherein the low-power, lowoperating temperature heat sources are placed at a lower level (below)the high-power, high operating temperature heat sources on an heatexchanger.

FIG. 1A is a schematic front elevation view of a heat exchanger 500,according to embodiments of the disclosures. FIG. 1B is a schematicdiagram of a right side view of a fin 100 of the heat exchanger 500,according to embodiments of the disclosure. The heat exchanger 500 isused to cool one or electronic devices. Referring to FIGS. 1A and 1B,the heat exchanger 500 includes a plurality of heat exchanger fins 100and which are thermally coupled to a base plate 190. Each heat exchangerfin 100 includes a fin base 119, a fin edge 111 opposite the fin base119, and an exchanger enhancement section portion 115 between the finbase 119 and fin edge 111. The base plate 190 includes a top or mountingsurface 191 and a bottom or contact surface 199 opposite the mountingsurface 191. The mounting surface 191 has a plurality of mountinggrooves 192 thereon, substantially parallel to each other and spacedapart at desired intervals.

The dimensions (e.g., length, breadth, thickness), depth, and number ofmounting grooves 192 correspond to the dimensions (e.g., length,breadth, thickness), height and number of fins 100. Each fin base 119 ofeach heat exchanger fin 100 is thermally and mechanically coupled toeach mounting groove 192 using suitable techniques such as brazingtechniques, for instance. However, other techniques can also be used aslong as heat may be efficiently and effectively transferred from thebase plate 190 to the plurality of heat exchanger fins 100. In someembodiments, each fin base 119 is hemmed, thereby reinforcing thestrength thereof and increasing the surface area for conductive heattransfer from the base plate 190 to the plurality of heat exchanger fins100. As illustrated, the hemmed portion of each fin 100 is inserted intothe base plate 190 for securely mounting each 100 to the base plate 190.

The area occupied by the plurality of heat exchanger fins 100 on themounting surface 191 may be varied depending upon the spacing betweenthe individual fins 100 and as required by application and design. As anexample, the fins 100 occupy a smaller area when the fins 100 areclosely positioned. This results in an empty, non-occupied portion ofthe mounting surface 191 that does not include fins 100.

One or more electronic devices generating heat (heat sources) areattached to the contact surface 199, for example by fasteners (e.g.,nuts, screws, bolts, pins, clips etc.) or by other means such as thermalpaste as long as heat from the electronic device is efficiently andeffectively transferred from the one or more electronic source to thebase plate 190. In some embodiments, multiple heat sources, for example,a first heat source 182 and a second heat source 188 are attached to thecontact surface 199 of the base plate 190. For the purposes ofdiscussion herein, it is assumed that the power requirement and maximumoperating temperature allowance of the first heat source 182 is lessthan that of the second heat source 188 and when in operation, the firstheat source 182 is positioned lower (e.g., closer to ground (G)) thanthe second heat source 188 on the fin 100.

FIG. 2A is a schematic diagram of a right side view of a fin 100 of theheat exchanger 500 of FIG. 1A and FIG. 1B without the base plate 190,according to embodiments of the disclosure. FIG. 2B is schematic diagramof a left side view of the heat exchanger fin in FIG. 1A, according toembodiments of the disclosure. Referring to FIGS. 2A and 2B, and withcontinued reference to FIGS. 1A and 1B, each heat exchanger fin 100includes a first evaporator region 120, a second evaporator region 130,a first condenser region 160, and a second condenser region 150, a loweredge 117, and an upper edge 118 longitudinally opposite the lower edge117.

It should be understood that the first evaporator region 120, the secondevaporator region 130, the first condenser region 160, and the secondcondenser region 150 are regions of the fin 100 generally indicated forthe sake of explanation. The first evaporator region 120 is located inthe lower left side of the fin 100 and is at least partially defined bythe lower edge 117 of the fin 100 and the fin base 119. The secondevaporator region 130 is located in the lower right side of the fin 100and is at least partially defined by the upper edge 118 of the fin 100and the fin base 119. The first condenser region 160 is located in theupper left side of the fin 100 and above the first evaporator region 120and is at least partially defined by the lower edge 117 of the fin 100and the fin edge 111. The second condenser region 150 is located in theupper right side of the fin 100 and above the second evaporator region130 and is at least partially defined by the upper edge 118 of the fin100 and the fin edge 111. The first and second evaporator regions 120,130 and first and second condenser regions 160, 150 form the exchangerenhancement portion 115 of each fin 100.

The second evaporator region 130 and the second condenser region 150include a plurality of obstructers 114 arranged in a matrix-typeformation and having a desired separation between each other. Asdiscussed elsewhere in this document, the plurality of obstructers 114are formed by bonding first and second metal sheets 183 and 187 (e.g.,the inner surfaces of thereof) of each fin 100 at one or more discretelocations, while the inner surfaces of the metal sheets 183 and 187 inthe portions around each obstructer 114 are not bonded to each other.The portions that are not bonded define a network of channels 116 (alsoreferred to as braided channels) that extends between the obstructers114. The plurality of obstructers 114 thus define a plurality ofrecessed portions formed in the outer surface of the second metal sheet187. In some embodiments, the number of the obstructers 114 (and therebythe number of channels 116) of the second condenser region 150 is atleast equal to or greater than the number of obstructers 114 (andthereby the number of channels 116) of the second evaporator region 130.

The second evaporator region 130 and the second condenser region 150further include at least a portion of a dividing obstructer 113. Thedividing obstructer 113 includes an evaporation side 144, a condensationside 146, and a flow side 145 connected to ends of the evaporation side144 and condensation side 146 adjacent the upper edge 118. Theevaporation side 144, the condensation side 146, and the flow side 145are defined by edges (or boundaries) created in the metal sheet 187 byselectively bonding the inner surfaces of the metal sheets 183 and 187.The evaporation and condensation sides 144, 146 are generally parallelto each other and separated from each other.

The evaporation side 144 extends between an evaporation side end 141 andthe flow side 145. The condensation side 146 extends between acondensation side end 151 and the flow side 145. As illustrated, theflow side 145 is angled with respect to the condensation side 146 andthe evaporation side 144. The flow side 145 includes a top end 147 wherethe flow side 145 and the condensation side 146 connect and a bottom end149 opposite the top end 147 where the flow side 145 and the evaporationside 144 connect. The top end 147 is closer to the upper edge 118 thanthe bottom end 149. This structure improves vapor flow from the secondevaporator region 130 to the second condenser region 150 and furtherincreases output pressure gain in downward working fluid flow of acondensation channel 162.

As illustrated, the dividing obstructer 113 defines a longitudinal axisX of the fin 100 and straddles portions of the second evaporator region130 and the second condenser region 150 about the axis X. The axis X isgenerally parallel to the fin base 119, and vertically separates thefirst condenser region 160 and second condenser region 150 from thefirst evaporator region 120 and second evaporator region 130. The axis Xgenerally defines the inner perimeters of the first evaporator region120, the second evaporator region 130, first condenser region 160, andsecond condenser region 150.

The plurality of obstructers 114 are generally circular-shaped having astaggered pitch. However, embodiments are not limited thereto and theplurality of obstructers 114 can have other shapes, such as polygonalshapes, and/or non-staggered pitches, depending upon application anddesign requirements.

The first condenser region 160 includes a condensation channel 162 andthe first evaporator region 120 includes an evaporation channel 122.Each of the condensation channel 162 and evaporation channel 122 areformed by selectively bonding portions of the inner surfaces of themetal sheets 183 and 187 that form the fin 100. The evaporator channel122 transports vapor generated due to heating of the working fluidflowing in the fin and the condensation channel 162 transports thecondensed vapor.

The condensation channel 162 is in fluid communication with theplurality of obstructers 114 and channels 116 of the second condenserregion 150 and the evaporation channel 122 is in fluid communicationwith the plurality of obstructers 114 and channels 116 of the secondevaporator region 130. The first condenser region 160 and the firstevaporator region 120 each further include at least a portion of aconnecting channel 172 that is in fluid communication with thecondensation channel 162 and the evaporation channel 122. A condensationchannel end 171 of the condensation channel 162 is defined by theconnection between the condensation channel 162 and the connectingchannel 172 and an evaporation channel end 121 of the evaporationchannel 122 is defined by the connection between the evaporation channel122 and the connecting channel 172. The condensation channel 162, theevaporation channel 122, and the connecting channel 172 are formed asraised structures on the outer surface of the second metal sheet 187, asopposed to the plurality of obstructers 114 that are formed as recesses.

The condensation channel 162 and the evaporator channel 122 are parallelto each other and the connecting channel 172 is inclined (greater than0° and less than 90°) with respect to the condensation channel 162 andthe evaporator channel 122. The evaporation channel end 121 is closer tothe edge 117 than the condensation channel end 171. This angled positionof the connecting channel 172 causes the working fluid from the downwardworking fluid flow to be driven upward into the second evaporator region130 from the evaporation channel 122.

A condensation channel end 161 of the condensation channel 162 isdefined by the connection between the condensation channel 162 and thechannels 116 of the second condenser region 150 and an evaporationchannel end 131 of the evaporation channel 122 is defined by theconnection between the evaporation channel 122 and the channels 116 ofthe second evaporator region 130. The condensation channel end 161defines a condenser partition between the first and second condenserregions 150, 160 perpendicular to the axis X, and the evaporationchannel end 131 defines an evaporator partition between the first andsecond evaporator regions 120, 130, perpendicular to the axis X.

The first evaporator region 120 is therefore defined by the fin base119, the axis X, the lower edge 117, and the evaporator partitionbetween the first and second evaporator regions 120, 130. The firstcondenser region 160 is defined by the axis X, the lower edge 117, finedge 111, and the condenser partition between the first and secondcondenser regions 150, 160. The second evaporator region 130 is definedby the axis X, the evaporator partition between the first and secondevaporator regions 120, 130, the fin base 119, and the upper edge 118.The second condenser region 150 is defined by the axis X, the fin edge111, the condenser partition between the first and second condenserregions 150, 160, and the upper edge 118.

In some other embodiments, the fin 100 includes more than onecondensation channel 162, more than one evaporation channel 122, andmore than one connecting channel 172, without departing from the scopeof the disclosure. As an example, embodiments include two condensationchannels communicating with one connecting channel or two connectingchannels communicating with one condensation channel and one evaporationchannel.

In some embodiments, the flow volume of the condensation channel 162,the evaporation channel 122, and the connecting channel 172 is eventhroughout the channels. However, embodiments are not limited in thisregard and the volume can be varied as required by application anddesign.

Each heat exchanger fin 100 is made of a first metal sheet 183 and asecond metal sheet 187 that are coupled to each other at thecorresponding ends to form the fin base 119 and fin edge 111. Asdiscussed above, the inner surfaces of the metals sheets 183 and 187 areselectively bonded to form the exchanger enhancement portion 115 thatincludes at least one condensation channel 162, at least one connectingchannel 172, at least one evaporation channel 122, a dividing obstructer113, plurality of obstructers 114 and channels 116. The first metalsheet 183 includes a first inner surface and the second metal sheet 187includes a second inner surface. The second inner surface at leastpartially defines the exchanger enhancement portion 115 that includesthe at least one condensation channel 162, the at least one connectingchannel 172, the at least one evaporation channel 122, the dividingobstructer 113, the plurality of obstructers 114, and channels 116.

In some embodiments, each of the plurality of heat exchanger fins 100 isunder vacuum and has a working fluid therein. The working fluid isdistributed in the form of liquid vapor slugs/bubbles throughout thechannels 116. Each heat exchanger fin 100 includes a main evaporatorregion (e.g., second evaporator region 130), a main condenser region(e.g., second evaporator region 150), vapor flow channels 116 extendingfrom the main evaporator region and the main condenser region, andworking fluid condenser channels (e.g., condensation channel 162),working fluid transport channels (e.g., connecting channel 172), andworking fluid evaporator channels (e.g., evaporation channel 122).

When heat from a first heat source 182 and a second heat source 188 isapplied to the first and second evaporator regions 120, 130 (fin base119), the heat converts the working fluid to vapor and the vapor bubblesincrease within the second evaporator region 130. Meanwhile, at thesecond condenser region 150, heat is removed and the bubbles decrease.The volume expansion due to vaporization and the contraction due tocondensation cause an oscillating motion within the channels (e.g., oneor more of the channels 116, the condensation channel 162, theconnecting channel 172, and the evaporation channel 122). The volume ofthe second condenser region 150 is at least equal to or greater than thevolume of the second evaporator region 130, facilitating the oscillatingmotion. The net effect of the temperature gradient between the secondevaporator region 130 and second condenser region 150 and the differencein vapor pressure in the channels 116 and working fluid channels (e.g.,condensation channel 162, one connecting channel 172, and evaporationchannel 122) creates a non-equilibrium pressure condition. The increasedoutput pressure gain in downward working fluid flow to the condensationchannel 162, increases upward oscillation driving forces throughout theconnecting channel 172 and the evaporation channel 122, and thusimproves the heat transfer efficiency rate along each fin edge 111 forelectronic devices that operate vertically, thereby improving thermalperformance. The evaporation channel end 121 is spaced from the groundcompared to the condensation channel end 171 to facilitate the workingfluid from the downward working fluid flow to be driven upward into thesecond evaporator region 130 from the evaporation channel 122.Thermo-fluidic transport is provided within each heat exchanger fin 100via the self-sustaining oscillation driving forces, whereby the pressurepulsations are thermally driven.

Thus, when the amount of working fluid in the condensation channel 162,the connecting channel 172, and the evaporation channel 122, andchannels 116 of the second evaporator region 130 and second condenserregion 150 is around 40% to around 80% (also referred to as a fillingratio), the amount of working fluid for efficient and effective thermalperformance is reduced by 40% to 60% when compared to prior art heatexchangers that do not include the condensation channel 162, theconnecting channel 172, and the evaporation channel 122, and channels116.

Weight of the plurality of heat exchanger fins 100 is reduced,eliminating the need for more costly attachment materials ornon-standard attachment mechanisms. Furthermore, via the evaporationchannel 122 and channels 116 of the evaporator region 130, an increasedamount of working fluid is contained in the evaporator region 130further away from ground. Thus, heat dissipation efficiency is drivenupward, opposite the direction of gravity, mitigating dry-out fromoccurring, causing the electronic device to overheat, fail or bedamaged. Even more, the lesser maximum operating temperature allowancefor lower-powered electronic devices is more compatibly met via theevaporation channel 122, and the greater maximum operating temperatureallowance for lower-powered electronic devices is more compatibly metvia the upward driven increase in heat dissipation efficiency. Whenthere are more than one heat source, as an example, three heat sources,a first heat source, a second heat source, and a third heat sourcebetween the first and second heat sources, heat dissipation efficiencyis increased for the second heat source, closest to the upper outerperimeters of the second evaporator region 130 and second condenserregion 150, when compared to existing heat exchangers. Thus, electronicdevices are limited from overheating, failing or being damaged via themore compatible matching of heat dissipation efficiency and power outputand maximum heat tolerance of the heat sources attached to the contactsurface 199 of the base plate 190.

The shape and width of the dividing obstructer 113, and lengths of thesecond evaporation and condensation sides 144, 146 may be varieddepending upon application and design requirements as long as the topend 147 of the dividing obstructer 113 is closer to the upper edge 118than the bottom end 149, and the volume of the channels 116 of thesecond condenser region 150 is at least equal to or greater than thevolume of the braided channels 116 of the second evaporator region 130.

FIG. 3A is a schematic perspective view of a heat exchanger fin 300,according to embodiments of the disclosure. FIG. 3B is a plan view ofthe heat exchanger fin 300 of FIG. 3A, according to embodiments of thedisclosure. The heat exchanger fin 300 may be similar in some respectsto the heat exchanger fin 100 in FIGS. 1A-2B, and therefore may be bestunderstood with reference thereto where like numerals designate likecomponents not described again in detail. Referring to FIGS. 3A and 3B,and with continued reference to FIGS. 1A to 2B, in the heat exchangerfin 300, the length of the second evaporation side 144 of the dividingobstructer 113 is longer than the length of the second condensation side146. Thus, for electronic devices that operate vertically, heatdissipation efficiency is higher near the ground (lower portion of thefin) because working fluid is accumulated at the lower portion of thefin and thus a heat source having an increased power output and heattolerance can be attached to the fin 300 closer to ground. In the heatexchanger fin 300, the top end 147 of the dividing obstructer 113 iscloser to the upper edge 118 than the bottom end 149, and the number ofchannels 116 of the second condenser region 150 is at least equal to orgreater than the number of the channels 116 of the second evaporatorregion 130. With reference to the orientation of the heat exchanger fin300 in FIGS. 3A and 3B, the condensation side end 151 is closer to theupper edge 118 in the longitudinal direction than the evaporation sideend 141, and the condensation channel end 161 and the evaporationchannel end 131 are collinear.

FIG. 4A is a schematic perspective view of a heat exchanger fin 400,according to embodiments of the disclosure. FIG. 4B is a plan view ofthe heat exchanger fin 400 of FIG. 4A, according to embodiments of thedisclosure. The heat exchanger fin 400 may be similar in some respectsto the heat exchanger fins 100 and 300 in FIGS. 1A-3B, and therefore maybe best understood with reference thereto where like numerals designatelike components not described again in detail. Referring to FIGS. 4A and4B, and with continued reference to FIGS. 1A to 3B, in heat exchangerfin 400, the length of the second evaporation side 144 of the dividingobstructer 113 is longer than the length of the second evaporation side144 in FIG. 3A, and is longer than the length of the second condensationside 146. Thus, for electronic devices, greater heat dissipationefficiency is obtained even closer to ground (lower portion of the fin)and thus a heat source having an increased power output and heattolerance can be attached to the fin 400 even more closer to ground. Inthe heat exchanger fin 400, the top end 147 of the dividing obstructer113 is closer to the upper edge 118 than the bottom end 149 and thenumber of the channels 116 in the condenser region 150 is at least equalto or greater than the number of the channels 416 in the evaporatorregion 130. With reference to the orientation of the heat exchanger fin400 in FIGS. 4A and 4B, the condensation side end 151 is closer to theupper edge 118 in the longitudinal direction than the evaporation sideend 141, and the evaporation channel end 131 is closer to the lower edge117 than the condensation channel end 161.

FIG. 5A is a perspective view of a heat exchanger fin 500, according toembodiments of the disclosure. FIG. 5B is a plan view of the heatexchanger fin 500 of FIG. 5A, according to embodiments of thedisclosure. The heat exchanger fin 500 may be similar in some respectsto the heat exchanger fins 100, 300, and 400 in FIGS. 1A-4B, andtherefore may be best understood with reference thereto where likenumerals designate like components not described again in detail.Referring to FIGS. 5A and 5B, and with continued reference to FIGS. 1Ato 4B, in the heat exchanger fin 500, the length of the secondevaporation side 144 of the dividing obstructer 113 is longer than thelength of the second condensation side 146, similar to the lengths inFIGS. 3A and 3B, and the width of the dividing obstructer 113 is widerthan the width in the fins 100, 300, and 400. The widening of thedividing obstructer 113 decreases the number of obstructers 114 and thechannels 116 of the second evaporator region 130. Thus, for electronicdevices, greater heat dissipation efficiency is obtained closer toground (lower portion of the fin) and thus a heat source having anincreased power output and heat tolerance can be attached to the fin 500closer to ground. Due to the increase in width of the dividingobstructer 113, working fluid volume in the fin is decreased and weightof the heat exchanger fin 500 is decreased. In the heat exchanger fin500, the top end 147 of the dividing obstructer 113 is closer to theupper edge 118 than the bottom end 149. With reference to theorientation of the heat exchanger fin 500 in FIGS. 5A and 5B, thecondensation side end 151 is closer to the upper edge 118 in thelongitudinal direction than the evaporation side end 141, and theevaporation channel end 131 and the condensation channel end 161 arecollinear. The number of the channels 116 of the second condenser region150 is at least equal to or greater than the number of the channels 516of the second evaporator region 530.

The plurality of heat exchanger fins 100, according to embodiments ofthe disclosure, having a working fluid under vacuum in the channels 116,compatibly matches heat dissipation and thermal performance with heatdissipation requirements and thermal performance requirements of morethan one heat source attached to the contact surface 199 of the baseplate 190. The condensation channel 162, the connecting channel 172, theevaporation channel 122, the channels 116 formed by the plurality ofobstructers 114, and the dividing obstructer 113, increase the creationof non-equilibrium pressure conditions and increase the self-sustainingturbulent driving forces within the condensation channel 162, theconnecting channel 172, and the evaporation channel 122, and thechannels 116.

In some embodiments, the first and second inner surfaces of the firstand second metal sheets 183, 187 are bonded together and integrallyformed at areas other than the condensation channel 162, the connectingchannel 172, the evaporation channel 122, and the dividing obstructer113, and the channels 116.

In some embodiments, each heat exchanger fin 100 is made of aluminum, oran aluminum-alloy or the like, and formed by roll-bonding or similarprocesses. FIG. 6 is a flow chart of a manufacturing method 600 of theheat exchanger fin 100 of FIG. 2A, according to embodiments of thedisclosure. The method 600 can also be used to manufacture fins 300,400, and 500. Referring to FIG. 6 , the method 600 includes a firstoperation 610 that includes providing a first metal sheet and a secondmetal sheet. In some embodiments, the first and second metal sheets aremetal coils, unrolled through an unwinder and then aligned by a suitableroller stand. Next, in operation 615, a pattern including a condensationchannel, a connecting channel, and an evaporation channel, and networkof channels is printed on the first metal sheet. In some embodiments,the sheets are cleaned and then printed by a screen printing processusing a graphite pattern to define the network of channels, thecondensation channel 162, the connecting channel 172, and theevaporation channel 122.

In some embodiments, each heat exchanger fin 100 further includes aworking channel 916 of a working section 918, extending from thechannels 116 to an edge of the heat exchanger fin 100. In someembodiments, the screen printing process employing the graphite patternalso prints the extended working channel 916. Following, in operation620, the inner surface of the first metal sheet and the inner surface ofthe second metal sheet are integrally bonded in areas other than thechannel printed areas.

The graphite serves as a release agent, thus, preventing the first andsecond metal sheets from integrally bonding in the areas of thepatterned network of channels. However, other types of materials canalso be used as the release agent provided the materials prevent thefirst and second metal sheets from integrally bonding in the areas ofthe channels after a roll-bonding operation (S620).

In some embodiments, the thickness of the first and second metal sheetsis around 0.250 mm to around 3.00 mm, and the roll bonding processreduces the combined thickness of the metal sheets (the clad material)by around 40% to 60%. However, the thicknesses of the sheets and thecombined thickness after roll bonding can be varied (increased ordecreased) depending upon the material, original thickness of thesheets, number of sheets, processes employed, and design requirementsfor effective and efficient thermal performance.

In some embodiments, the heat exchanger fins 100, 300, 400, and 500 arequadrilateral shaped, However, the embodiments are not limited in thisregard, and the heat exchanger fins may be any desired shape, and asrequired by application and design requirements as long as a pressuredifferential is created in the fins to generate self-sustainingturbulent driving forces that cause the working fluid to flow in thechannels.

FIG. 7A is schematic drawing of a perspective view of the heat exchangerfin 100 of FIG. 1A and FIG. 1B following operation 620 of themanufacturing method 600 of FIG. 6 , according to embodiments of thedisclosure. Referring to FIG. 7A, with continued reference to FIG. 6 ,in operation 630, a working pipe 917 is inserted and secured to theworking channel 916, extending from the end of the working section 918.The working pipe 917 allows for communication with the outsideatmosphere and the condensation channel, connecting channel, evaporationchannel, and the network of channels. In operation 640, the channels116, the condensation channel 162, the connecting channel 172, and theevaporation channel 122 are inflated by introducing a fluid (e.g., gasor liquid) having a pressure that provides even inflation throughout theheat exchanger fin 100. In some embodiments, the gas is atmospheric airhaving a suitable pressure for inflation. In other embodiments, the gasmay be nitrogen, oxygen, argon, hydrogen, carbon dioxide, or any othersuitable gas or mixtures thereof. In some embodiments, the first andsecond metal sheets 183, 187 are inserted into a mold before inflatingfor even inflation throughout each heat exchanger fin 100.

In some embodiments, the radius (or height) of the condensation channel,the connecting channel, the evaporation channel, and the network of thechannels is around 0.125 mm to around 1.50 mm. However, embodiments arenot limited in this regards and the radius of the condensation channel,connecting channel, evaporation channel, and network of channels can bevaried (increased or decreased) depending upon the material, originalthickness of the metal sheets, number of sheets, processes used, anddesign requirements for effective and efficient thermal performance.

Next, in operation 650 a working fluid is introduced into the workingpipe and air is vacuumed out. FIG. 7B is a plan view of the heatexchanger fin of FIG. 7A following operation 660 of the manufacturingmethod 600 of FIG. 6 , according to embodiments of the disclosure.Referring to FIG. 7B, in operation 660, the working pipe 917 is closedand sealed by flattening and bonded, and after cooling, the workingchannel 916 and the working pipe 917 are cut and the heat exchanger fin100 is obtained.

In some embodiments, the diameter of the plurality of obstructers 114 isaround 0.500 mm to around 6.00 mm. The obstructers 114 can have the samediameter or different diameter. However, the diameter can be increasedor decreased depending upon the material, original thickness of themetal sheets, number of sheets, processes used, and design requirementsfor effective and efficient thermal performance, as long as the channels116 formed by the plurality of obstructers 114 increase the creation ofthe non-equilibrium pressure condition within the channels 116 andmaintain the self-sustaining turbulent driving forces therein.

In some embodiments, the first metal sheet 183 and second metal sheet187 are made of aluminum, or an aluminum-alloy or the like, and formedbonded by roll-bonding. However, in other embodiments, othermanufacturing processes, such as stamping can be used to bond the firstmetal sheet 183 and second metal sheet 187 depending on material andmanufacturing requirements. In some embodiments, the first metal sheet183 and/or the second metal sheet 187 may be made of copper, or acopper-alloy, or other malleable heat conducting metal having a highthermal conductivity as required by application and design requirements.

In some embodiments, the base plate 190 is made of aluminum, or analuminum-alloy, or any other material that can be used in a brazingtechnique for brazing of each fin base 119 of each heat exchanger fin100 to each mounting groove 192. In other embodiments, the base plate190 may also be made of copper, or a copper-alloy, or other malleableheat conducting metals having a high thermal conductivity as required byapplication and design requirements and as long as each fin base 119 canbe thermally and mechanically mounted to each mounting groove 192.

In some embodiments, the base plate 190 is made of a solid malleablemetal heat conducting material having a relatively high thermalconductivity. In some embodiments, the base plate 190 is under vacuum,and has a working fluid therein. In some embodiments, the base plate 190has an inlet and an outlet, having working fluid flowing therein.

In some embodiments, when a stamping process or the like is used to formthe heat exchanger fin 100, any desired bonding method, such asultrasonic welding, diffusion welding, laser welding and the like, canbe employed to bond and integrally form the first and second innersurfaces together at areas other than the areas including thecondensation channel, connecting channel, and evaporation channel, andnetwork of channels.

In some embodiments, when a stamping process or similar is employed,depending upon dimensions and application, axial or circumferential wickstructures, having triangular, rectangular, trapezoidal, reentrant, etc.cross-sectional geometries, may be formed on inner surfaces of one ormore of the condensation channel, the connecting channel, theevaporation channel, and the network of channels. The wick structure maybe used to facilitate the flow of condensed fluid by capillary forceback to the evaporation surface, keeping the evaporation surface wet forlarge heat fluxes.

In other embodiments, further heat treatment processes can be employedthroughout the manufacturing method of the heat exchanger fin 100.Additionally, one or more additional steps can be added to the processin order to incorporate additional features into the finished product.Also, the order of operations can be altered or new operations can beadded or some of the operations can be performed simultaneously. Forexample, other operations can include operations of alloying, casting,scalping and pre-heating, operations such as annealing; and operationssuch as solution heat treatment or final annealing, stretching,leveling, slitting, edge trimming and aging, and the like.

In some embodiments, the heat exchanger fin 100 includes a one sidedinflated roll-bonded sheet having the condensation channel, connectingchannel, evaporation channel, and network of channels. In alternativeembodiments, one or more heat exchanger fins 100 can include the atleast one condensation channel, connecting channel, evaporation channel,and network of channels on two sides thereof via two one sided inflatedroll-bonded sheets. In other embodiments, a single heat exchanger fin100 including the one sided inflated roll-bonded sheet having thecondensation channel, connecting channel, evaporation channel, andnetwork of channels, may be employed as a stand-alone heat exchanger.

In some embodiments, the working fluid includes acetone cyclopentane orn-hexane, or any other desired working fluid as long as the workingfluid can be vaporized by a heat source and the vapor can condense backto the working fluid and flow back to the heat source.

FIG. 8 is a schematic perspective view of a heat exchanger 800,according to embodiments of the disclosure. The heat exchanger 800 is anexample of a heat dissipation device used to dissipate heat generated byone or more electronic devices (e.g., circuits, processors, etc.).Although embodiments are discussed with reference to a heat exchanger,embodiments are equally applicable to other types of heat dissipationdevices without departing from the scope of the disclosure. Referring toFIG. 8 , the heat exchanger 800 includes a plurality of heat exchangerfins 851 arranged on a base plate 890. Each heat exchanger fin 851 is alongitudinally extending structure having a fin body 815 formed from afirst metal sheet 850 and a second metal sheet 820 coupled to eachother. The fin body 815 includes a fin base 819 along a firstlongitudinal edge and a fin edge 811 defining a second longitudinal edgeof the fin 851 opposite the fin base 819. The base plate 890 includes amounting surface 891 and a contact surface 899 opposite the mountingsurface 891. The mounting surface 891 includes a plurality of mountinggrooves 892 arranged substantially parallel to each other and evenlyspaced from each other.

Each mounting groove 192 is sized and shaped, or otherwise configured,to receive the fin base 819 of corresponding heat exchanger fin 851. Thefin base 819 of each heat exchanger fin 851 is thermally andmechanically coupled to each mounting groove 892 using adhesiontechniques, such as brazing. However, other suitable techniques forthermally and mechanically coupling the fins can be used. In someembodiments, each fin base 819 is hemmed (or bent), reinforcing thestrength thereof and increasing the surface area for conductive heattransfer from the base plate 890 to the plurality of heat exchanger fins100.

The area occupied by the plurality of heat exchanger fins 851 on themounting surface 891 varies depending upon application and designrequirements. For example, the area occupied by the fins 851 may besmaller, resulting in a non-occupied (empty) space on the mountingsurface 891, or the area occupied by the fins 851 may be larger when thespacing between adjacent fins 851 is increased.

In some embodiments, the thickness of the first and second metal sheets850 and 820 is around 0.250 mm to around 3.00 mm.

One or more heat sources, e.g., electronic devices are coupled to thecontact (or bottom) surface 899, for example, using fasteners and orother suitable means. In addition, to improve thermal conduction betweenthe electronic devices and the base plate 890, thermal paste or similaris used when coupling the electronic devices to the base plate 890.

FIG. 9A is schematic perspective view of a heat exchanger fin 851 of theheat exchanger 800 of FIG. 8 illustrating an outer surface 801 of thefirst metal sheet 820 of the fin 851, according to embodiments of thedisclosure. FIG. 9B is schematic perspective view of heat exchanger fin851 of FIG. 9A illustrating an outer surface 803 of the second metalsheet 850 of the fin 851, according to embodiments of the disclosure.Referring to FIGS. 9A and 9B, and with continued reference to FIG. 8 ,the fin body 815 of each heat exchanger fin 851 includes a plurality ofairflow through holes 814 formed through the fin body 815 and extendingfrom the outer surface 801 to the outer 803. The through holes 814define a network of channels 816 (also referred to as braided channels).The airflow through holes 814 are generally circular-shaped and arrangedin a staggered configuration. However, the shape and size of the holes814 is not limited to any particular shape and size. For instance, theholes 814 can be polygonal shape. The holes 814 can be arranged in anydesired configuration (staggered or non-staggered) and the separation(pitch) between adjacent holes 814 can be varied (increased ordecreased) as required by application and design.

In the absence of the through holes 814, air between adjacent heatexchanger fins 851 insulates the surfaces of the adjacent facing heatexchanger fins 851 and the base plate surfaces therebetween. This air isrelatively stagnant and does not flow freely between the fins. As aresult, heat dissipation is poor and thus thermal performance of heatexchangers decreases. The availability of only natural convection andthe reduced distance between the heat exchanger fins further decreaseheat dissipation. The plurality of airflow through holes 814, accordingto embodiments of the disclosure, result in air flowing through in thethrough holes 814 and between adjacent fins 851. This air flow istransverse to the air flowing longitudinally across the surfaces of eachheat exchanger fin 851 along the fin base 119. The transverse air flowscreate a turbulent airflow and thus reduces the presence of stagnant airbetween heat exchanger fins 851. By reducing stagnant air using theplurality of airflow through holes 814, the distance (separation)between the plurality of heat exchanger fins 100 can be reduced withoutsacrificing heat dissipation and thermal performance even when onlynatural convection is available. As a result, the average amount of heattransferred from each square centimeter of surface area of the pluralityof heat exchanger fins 1000 is increased.

In some embodiments, each heat exchanger fin 851 is quadrilateralshaped. However, the heat exchanger fins 851 can have any shape otherthan shape, e.g., polygonal, without departing from the scope of thedisclosure.

In some embodiments, each heat exchanger fin 851 further includes aworking channel 916 that connects the channels 816 to peripheral edge817 of a heat exchanger fin 851. The working channel 916 is used tointroduce working fluid into the channels 816 and for inflating the fin851 during the manufacturing process.

FIG. 10 is a partial cross-sectional view of the heat exchanger fin 851of FIG. 9A along line B-B and between lines C-C and D-D of FIG. 9A,according to embodiments of the disclosure. Referring to FIG. 10 , withcontinued reference to FIGS. 8-9B, the first metal sheet 850 includes asurface 852 and the second metal sheet 820 includes an inner surface822. The inner surface 852 contacts the inner surface 822 except inlocations where the channels 816 are located. The inner surface 852 andthe inner surface 822 cooperatively define the channels 816.

The plurality of airflow through holes 814 are defined in locationswhere the inner surface 852 contacts the inner surface 822. The firstmetal sheet 850 and the second metal sheet 820 cooperatively define eachairflow through hole 814 in locations where the inner surface 852contacts the inner surface 822. In some embodiments, and as illustrated,each airflow through hole 814 is located in a recess 821 formed in thesurface 801 of the second metal sheet 820.

Referring to FIGS. 9A and 10 , the channels 816 and the plurality ofairflow through holes 814 are formed in a region 830 of each fin 851that is separated from the edges of the fin 851. Outside the region 830,the fin 851 does not include airflow through holes 814, and the innersurface 852 and the inner surface 822 are in continuous contact witheach other.

In some embodiments, the plurality of heat exchanger fins 100 are undervacuum and include a working fluid. In some embodiments, the workingfluid is in the form of liquid vapor slugs/bubbles in the channels 816.In general, each heat exchanger fin 851 includes an evaporator region, acondenser region, and vapor flow channel regions extending between theevaporator region and the condenser region. When heat from at least oneheat source is applied to the evaporator region, the heat converts theworking fluid to vapor and the vapor expands within the heat exchangerfin 851. Meanwhile, at the condenser region, heat is being removed andthe vapor is condensed. The volume expansion due to vaporization and thecontraction due to condensation cause a turbulence motion via thechannels 816. The net effect of the temperature gradient between theevaporator region and the condenser region, and the driving forces dueto the different vapor flow paths created by the channels 816 creates anon-equilibrium pressure condition. Thus, thermo-fluidic transport isprovided via self-sustaining turbulent driving forces, having pressurepulsations being fully thermally driven.

The plurality of heat exchanger fins 100 under vacuum and including aworking fluid in the channels 816 increases heat dissipation and thermalperformance of the fins 100 compared to heat exchanger fins notincluding a working fluid. The channels 816 formed by the plurality ofairflow through holes 814 having staggered pitch increases the creationof non-equilibrium pressure conditions, strengthening theself-sustaining turbulent driving forces within the channels 816. Inaddition, the heat exchanger fins 100 minimize formation of a layer ofheated air on the surface of base plate 890 that impedes heat transfer.

In some embodiments, the first and second inner surfaces 852 and 822 ofeach fin 851 are bonded together at portions of the fin 851 that do notinclude the channels 816. In some embodiments, each heat exchanger fin851 is made of aluminum, or an aluminum-alloy or the like, and formed byroll-bonding.

FIG. 11 is a flow chart illustrating a manufacturing method 1100 of theheat exchanger fin 851 of FIG. 9A, according to embodiments of thedisclosure. Referring to FIG. 11 , with continued reference to FIGS. 8to 10 , the method 1100 of manufacturing each heat exchanger fin 851includes an operation 1110 of providing a first metal sheet 850 and asecond metal sheet 820. In some embodiments, the first and second metalsheets are metal coils that are unrolled using an unwinder and thenaligned by a suitable roller stand. Next, in operation 1115, a patternof channels 816 is printed on the first metal sheet 850 (oralternatively on the second metal sheet 820). In some embodiments, thesheets are cleaned and then printed by a screen printing process using agraphite pattern of the channels. In some embodiments, the screenprinting process using the graphite pattern also prints the workingchannel 916. Following, in operation 1120, the inner surface 852 of thefirst metal sheet 850 and inner surface 822 of the second metal sheet820 are integrally bonded in areas other than areas where the channelsare printed.

Those of ordinary skill in the relevant art will understand thatgraphite serves as a release agent, thus preventing the first and secondmetal sheets from bonding together in the areas of the patternedchannels. However, embodiments are not limited in this regard and othertypes of materials (or methods) can also be used as release agents toselectively bond the first and second metal sheets.

In some embodiments, the thickness of each of the first and second metalsheets 850, 820 can be reduced to around 40% to 60%. However,embodiments are not limited in this regard. In other embodiments, thethickness can be reduced to less than 40% or more than 60% dependingupon the material of the metal sheets, the original thickness of thesheets, the number of sheets bonded, and application and designrequirements.

Next, in operation 1130 a working pipe is inserted and secured to theworking channel 916. The working pipe provides for communication betweenthe channels 816 and the external atmosphere. Following, in operation1140, the channels are inflated by introducing a fluid (e.g., gas orliquid) having a pressure that causes even inflation throughout eachheat exchanger fin 851. In some embodiments, the fluid includesatmospheric air having a pressure suitable for inflation. In otherembodiments, the fluid include nitrogen, oxygen, argon, hydrogen, carbondioxide, or mixtures thereof. In some embodiments, the fluid includes aliquid under pressure. In some embodiments, the first and second metalsheets 850, 820 are inserted into a mold before inflating for eveninflation throughout each heat exchanger fin 851.

In some embodiments, the cross-sectional width of the channels 816 isaround 0.125 mm to around 1.50 mm. However, embodiments are not limitedthereto, and the width of the channels 816 can be increased or decreaseddepending upon the material of the sheets, original thickness of thesheets, the number of sheets bonded, and application and designrequirements, without departing from the scope of the disclosure.

Next, in operation 1150 a working fluid is introduced into the channels816 via the working pipe and the fluid used to inflating is vacuumedout. In operation 1160, the working pipe is closed and sealed byflattening and then bonding the metals sheets together. After cooling,the working pipe is cut and the plurality of airflow through holes areformed, e.g., using a punching process, in the locations where the metalsheets 820 and 850 are bonded to each other.

In some embodiments, the diameter of the plurality of airflow throughholes 814 is the same and is around 0.500 mm to around 6.00 mm. However,the diameter can be increased or decreased depending upon the materialof the sheets original thickness of the sheets, the number of sheetsbonded, and application and design requirements, without departing fromthe scope of the disclosure.

In some embodiments, the first metal sheet 850 and the second metalsheet 820 are made of aluminum, or an aluminum-alloy or the like, andformed by roll-bonding. However, in other embodiments the first metalsheet 850 and the second metal sheet 820 are formed by other methodssuch as stamping. In other embodiments, the first metal sheet 850 andthe second metal sheet 820 are made of copper, or a copper-alloy or thelike, or other malleable metal heat conducting material having arelatively high thermal conductivity.

In some embodiments, the base plate 890 is made of aluminum, or analuminum-alloy or the like that is suitable for utilizing a brazingtechnique for thermal and mechanical brazing the fin base 819 of eachheat exchanger fin 851 to a mounting groove 892. However, in otherembodiments the base plate 890 is made of copper, or a copper-alloy orthe like, or other malleable metal heat conducting material having arelatively high thermal conductivity provided each fin base 819 can bethermally and mechanically mounted to the mounting groove 892.

In some embodiments, the base plate 890 is made of a solid malleablemetal heat conducting material having a relatively high thermalconductivity. In other embodiments, the base plate 890 is under vacuum,and includes a working fluid therein. In still other embodiments, thebase plate 890 has an inlet and an outlet for introducing the workingfluid and for removing the working fluid.

In some embodiments, when a stamping process is used to form each heatexchanger fin 851, a bonding method such as ultrasonic welding,diffusion welding, laser welding and the like, can be used to bond andintegrally form the first and second inner surfaces 852 and 822.

In some embodiments, an axial or circumferential wick structure havingtriangular, rectangular, or trapezoidal cross-sectional geometries, isformed on inner surfaces of the channels 816. The wick structure is usedto facilitate the flow of condensed fluid by capillary force back to theevaporation surface, keeping the evaporation surface wet for large heatfluxes.

Those of ordinary skill in the relevant art will understand that furtherheat treatment processes can be employed throughout the manufacturingmethod of each heat exchanger fin 851, and the embodiments are notlimited to those described herein. Additional operations can be added tothe process in order to incorporate additional features into thefinished product. Also, the order of the operations can be changed. Forexample, operations of alloying, casting, scalping and pre-heating,intermediate annealing, and operations such as solution heat treatmentor final annealing, stretching, leveling, slitting, edge trimming andaging, and the like can be used.

In some embodiments, each heat exchanger fin 851 includes a one sidedinflated roll-bonded sheet having channels 816. In other embodiments,each heat exchanger fin 851 may include channels on two sides thereofvia two one sided inflated roll-bonded sheets. In other embodiments,each heat exchanger fin 851 including the one sided inflated roll-bondedsheet having channels 816 is used as a stand-alone heat exchanger. Insome embodiments, the working fluid includes acetone. Other workingfluids including cyclopentane or n-hexane can also be used.

FIG. 12A is a side view of a heat exchanger 1200 in FIG. 12B in thedirection of arrow M, according to embodiments of the disclosure. FIG.12B is a schematic perspective view of a heat exchanger 1200, accordingto embodiments of the disclosure. The heat exchanger 1200 is an exampleof a heat dissipation device used to dissipate heat generated by one ormore electronic devices (e.g., circuits, processors, etc.) coupledthereto. Although embodiments are discussed with reference to a heatexchanger, embodiments are equally applicable to other types of heatdissipation devices without departing from the scope of the disclosure.Referring to FIGS. 12A and 12B, the heat exchanger 1200 includes aplurality of heat exchanger fins (or fin blades) 1250 installed on abase plate 1290. Each heat exchanger fin 1250 includes a fin base 1219,a fin intermediate 1212 and a fin tip 1211. Each fin 1250 is a bentstructure (L-shaped) including an exchanger enhancement portion 1215disposed transverse (e.g., having angle greater than 0° and less than180°) to the base plate 1290 and an auxiliary enhancement portion 1213extending transversely (e.g., having angle greater than 0° and less than180° from the exchanger enhancement portion 1215. Thus, referring toorientation in FIGS. 12A and 12B, the exchanger enhancement portion 1215forms the vertical portion of the fin 1250 and the auxiliary enhancementportion 1213 forms the horizontal portion of the fin 1250. The auxiliaryenhancement portion 1213 is connected to the exchanger enhancementportion 1215 via a bend (or curve) 1270.

However, it should be noted that the angle of the exchanger enhancementportion 1215 with reference to the base plate 1290 can be greater than0° or less than 90° and the angle of the auxiliary enhancement portion1213 with reference to the exchanger enhancement portion 1215 can begreater than 0° or less than 90°, without departing from the scope ofthe disclosure. The base plate 1290 includes a mounting surface 1291 anda contact surface 1299 opposite the mounting surface 1291. The mountingsurface 1291 has a plurality of mounting grooves 1920, each of which issized and shaped, other otherwise configured, to receive and securetherein a corresponding fin 1250. The mounting grooves 1920 are arrangedsubstantially parallel to each other and spaced apart at even or regularintervals (or, in some embodiments, at irregular intervals).

Each mounting groove 1920 receives in it a fin base 1219 of each heatexchanger fin 1250. The fin base 1219 of each heat exchanger fin 1250 isthermally and mechanically attached (e.g., permanently) to each mountinggroove 1920 by brazing techniques. However, other methods may be used aslong as heat is efficiently transferred from the base plate 1290 to theplurality of heat exchanger fins 1250. In some embodiments, each finbase 1219 is hemmed to improve the strength thereof and increase thesurface area of the fin 1250 in contact with the base plate 1290 forincreasing heat transfer from the base plate 1290 to the heat exchangerfins 1250.

The area occupied by the heat exchanger fins 1250 on the mountingsurface 1291 may depend upon application and design requirements. As anexample, in some embodiments, the fins 1250 are closely placed to eachother and thus the area occupied by the fins 1250 on the mountingsurface 1291 is smaller, resulting in portions of the mounting surface1291 surrounding the fins 1250 that are not occupied by the fins 1250.

One or more electronic devices (heat sources) are attached to thecontact surface 1299, for example, using fasteners (nut, bolts, screws,pins, clips etc.). In some embodiments, a thermal paste is used whenattaching the electronic devices to the contact surface 1299 forimproved heat transfer.

In some embodiments, a first heat source 1282 and a second heat source1288 are attached to the contact surface 1299 of the base plate 1290.The power requirement and maximum operating temperature allowance of thefirst heat source 1282 may be less than that of the second heat source1288 and in operation, the first heat source 1282 is located lower(closer to ground G (or base) transverse to the horizontal (H) level)than the second heat source 1288 when the when the heat exchanger 1200is installed in an upright (vertical) position. With reference to theorientation of the heat exchanger 1200 in FIG. 12B, when the heatexchanger 1200 is installed in an upright (vertical) position, the leftside ends of the base plate 1290 and the fins 1250 are closer to theground G. However, embodiments are not limited thereto and more than twosources of heat can be coupled to the base plate 1290.

FIG. 13A is a side view of a heat exchanger fin 1250 of the heatexchanger of FIG. 12A and FIG. 12B in the direction of arrow M in FIG.12B, according to embodiments of the disclosure. FIG. 13B is a schematicperspective view of the heat exchanger fin 1250 of FIG. 13A, accordingto embodiments of the disclosure. FIG. 13C is a side view of the heatexchanger fin 1250 of FIGS. 13A and 13B in the direction of arrow N,according to embodiments of the disclosure. FIG. 13D is a side view ofthe heat exchanger fin 1250 of FIGS. 13A and 13B in the direction ofarrow P, according to embodiments of the disclosure. FIG. 14A is aschematic view of a first metal sheet 1283 of the heat exchanger fin1250 of FIGS. 12A-13D, according to embodiments of the disclosure. FIG.14B is a view of a second metal sheet 1287 of the heat exchanger fin1250 of FIGS. 12A-13D, according to embodiments of the disclosure.

Referring to FIGS. 13A to 14B, with continued reference to FIGS. 12A and12B, each heat exchanger fin 1250 includes a body 1201 formed of a firstmetal sheet 1283 having a first inner surface and a second metal sheet1287 having a second inner surface. The first and second metal sheets1283 and 1287 are coupled to each other via a first inner surface 1285of the first metal sheet 1283 and a second inner surface 1289 of thesecond metal sheet 1287. When coupled, the first and second innersurfaces 1285, 1289 face each other. The first and second metal sheets1283 and 1287 together form the fin base 1219, the fin intermediateregion 1212, the fin tip 1211, the auxiliary enhancement portion 1213,and the exchanger enhancement portion 1215. The auxiliary enhancementportion 1213 includes a condensation channel 1237 and multiple auxiliarychannels 1247 (FIG. 13B), and the exchanger enhancement portion 1215includes multiple connecting channels 1227 (FIG. 13B) and an evaporationchannel 1253.

Referring to FIGS. 14A and 14B, the first metal sheet 1283 forms agenerally upper portion of each fin 1250 and the second metal sheet 1287forms a generally lower portion of the each fin 1250. The inner surfaces1285 and 1289 of the first metal sheet 1283 and the second metal sheet1287, respectively, contact each other at locations in the fin 1250 thatdo not include the condensation channel 1237, the auxiliary channels1247, the connecting channels 1227, and the evaporation channel 1253.Each of the first metal sheet 1283 and the second metal sheet 1287defines a portion of the condensation channel 1237, the auxiliarychannels 1247, the connecting channels 1227, and the evaporation channel1253. The first metal sheet 1283 includes first portion 1237 a of thecondensation channel 1237, first portions 1247 a of each of theauxiliary channels 1247, first portions 1227 a of each of the connectingchannels 1227, and first portion 1253 a of the evaporation channel 1253.Each of the first portions 1237 a, 1247 a, 1227 a, and 1253 a in thefirst metal sheet 1287 is formed as a recess on the first inner surface1285 of the first metal sheet 1283.

Similarly, the second metal sheet 1287 includes second portion 1237 b ofthe condensation channel 1237, second portions 1247 b of each of theauxiliary channels 1247, second portions 1227 b of each of theconnecting channels 1227, and second portion 1253 b of the evaporationchannel 1253. Each of the second portions 1237 b, 1247 b, 1227 b, and1253 b in the second metal sheet 1289 is formed as a recess in thesecond inner surface 1289 of the first metal sheet 1283. The firstportions 1237 a, 1247 a, 1227 a, and 1253 a and the second portions 1237b, 1247 b, 1227 b, and 1253 b together define the correspondingcondensation channel 1237, auxiliary channels 1247, connecting channels1227, and evaporation channel 1253.

In some embodiments, the condensation channel 137 extends longitudinallyalong the auxiliary enhancement region 1213 and at or adjacent the fintip 1211. Each of the multiple auxiliary channels 147 are in fluidcommunication with the condensation channel 1237. The exchangerenhancement portion 1215 includes the evaporation channel 1253 extendinglongitudinally at or adjacent along the fin base 1219, and multipleconnecting channels 127 in fluid communication with the evaporationchannel 1253. The number of auxiliary channels 147 corresponds to thenumber of connecting channels 127 and each auxiliary channel 127 is influid communication with a corresponding connecting channel 127. Assuch, the condensation channel 137, the multiple auxiliary channels 147,the multiple connecting channels 127, and the evaporation channel 153are all in fluid communication with each other. The auxiliary channels147 and the connecting channels 127 are disposed in parallel at regularintervals and at an incline (angle greater than 0° or less than 90°)with respect to the evaporation channel 153 and the condensation channel137. The evaporation channel 153 and the condensation channel 137 aredisposed substantially parallel (+/−1-2°) to each other. The angle ofthe auxiliary channels 147 and the connecting channels 127 is notlimited to any particular angle. The auxiliary channels 147 and theconnecting channels 127 can be orientated at any desired angle as longas working fluid in the auxiliary channels 147 and the connectingchannels 127 flows in a downward direction during operation when theheat exchanger 1200 is installed in an upright position.

Although only a single condensation channel 137 and a single evaporationchannel 153 are discussed herein, embodiments are not limited in thisregard and the heat exchanger 1200 can include more than onecondensation channel 137 and more than one evaporation channel 153,without departing from the scope of the disclosure. When more than onecondensation channel 137 and evaporation channel 153 are installed, theconnecting channels 127 are in fluid contact with each evaporationchannel 153 and the auxiliary channels are in fluid contact with eachcondensation channel 137.

In some embodiments, a volume of the working fluid that flows throughunit volumes of the condensation channel 1237 and the evaporationchannel 1253 is generally uniform across the entirety of each channeland is around two times the flow volume the channels 147 and theconnecting channels 127. However, embodiments are not limited theretoand the cross-sectional area and/or length of the condensation channel1237 and the evaporation channel 1253 can be varied as required byapplication and design, and without departing from the scope of thedisclosure.

In some embodiments, each heat exchanger fin 1250 is under vacuum andincludes a working fluid therein. The working fluid is in the form ofliquid vapor slugs/bubbles throughout the auxiliary channel 1247 of theauxiliary enhancement region 1213 and the connecting channel 1227 andthe evaporation channel 1253 of the exchanger enhancement portion 1215.Each heat exchanger fin 1250 includes an evaporator region (includingthe evaporation channel 1253), a condenser region (including thecondensation channel 1237), vapor flow region (including the auxiliarychannels 147 and the connecting channels 127) extending from theevaporator region and condenser region, respectively.

When heat from the first heat source 1282 and the second heat source1288 is applied to the contact surface 1299 of the base plate 1290, theheat converts the working fluid to vapor and the vapor bubbles increasein size and number within the vapor flow region. Meanwhile, at thecondenser region, heat is removed (dissipated) and the bubbles arereduced. The volume expansion of the working fluid due to vaporizationand the contraction due to condensation causes an oscillating motionwithin the condensation channel 1237, the auxiliary channels 1247, theconnecting channels 1227, and the evaporation channel 1253. The volumeof the condenser region is at least equal to or greater than the volumeof the evaporator region, thereby facilitating the oscillating motion.The net effect of the temperature gradient between the evaporator regionand condenser region and the pressure differences introduced throughoutthe condensation channel 1237, the auxiliary channels 1247, theconnecting channels 1227, and the evaporation channel 1253 creates anon-equilibrium pressure condition. As a result of the increased outputpressure gain in downward working fluid flow through the auxiliarychannels 1247, a portion of the connecting channels 1227 boosts upwardoscillation driving forces throughout the evaporation channel 1253 andother portion of the connecting channels 1227, and increased surfacearea of the auxiliary enhancement portion 1213, improving the heattransfer efficiency rate for the heat sources (electric devices).Thermo-fluidic transport is thus provided within each heat exchanger fin1250 via the self-sustaining oscillation driving forces, whereby thepressure pulsations are thermally driven.

Those of ordinary skill in the relevant art will appreciate that theshape, width and lengths of the condensation channel 1237 and theauxiliary channels 1247 of the auxiliary enhancement portion 1213 andthe connecting channels 1227 and the evaporation channels 1253 of theexchanger enhancement portion 1215 may be varied, such as having a wavyshape, having increased or decreased widths, having longer or shorterlengths, or any combination thereof, depending upon application anddesign requirements, without departing from the scope of the disclosure.

The plurality of heat exchanger fins 1250 under vacuum and including aworking fluid in the condensation channel 1237, the auxiliary channels1247, the connecting channels 1227, and the evaporation channel 1253increases the heat dissipation and thermal performance of each heatexchanger fin 1250 when compared existing heat exchanger fins that donot include the channel structure including a working fluid. Also, theauxiliary enhancement portion 1213 increases the surface area of theheat source(s) (e.g., electronic devices) in thermal contact with theheat exchanger while keeping the space occupied by the heat exchangerminimal. Thus, the rate of convective heat transfer is further improvedwhile preventing formation of a layer of heated air on the surface ofbase plate 1290 that impedes heat transfer.

In some embodiments, each heat exchanger fin 1250 is made of aluminum,or an aluminum-alloy or the like, and formed by roll-bonding. FIG. 15 isa flow chart illustrating a manufacturing method 1500 of the heatexchanger fin 1250 of FIGS. 12A and 12B, according to embodiments of thedisclosure. Referring to FIG. 15 , with continued reference to FIGS. 12Ato 14B, the method 1500 of manufacturing the heat exchanger fin 1250under vacuum and including a working fluid therein, generally includesoperation 410 for providing a first metal sheet 1283 and a second metalsheet 1287. In some embodiments, the first and second metal sheets 1283,1287 are metal coils, unrolled using an unwinder and then aligned by asuitable roller stand. Next, in operation 415, a pattern of thecondensation channel 1237, the auxiliary channels 1247, the connectingchannels 1227, and the evaporation channel 1253 are printed on the firstmetal sheet 1283 (or the second sheet 1287). In some embodiments, thesheets are cleaned and then printed using a screen printing process thatuses a graphite pattern of the condensation channel 1237, the auxiliarychannels 1247, the connecting channels 1227, and the evaporation channel1253.

In some embodiments, each heat exchanger fin 1250 further includes aworking channel 1221 (FIGS. 13B and 16A) extending from one end of theworking section 521 of each heat exchanger fin 1250. In someembodiments, the screen printing process employing the graphite patternalso prints the working channel. Following, in operation 420, the firstinner surface 1285 of the first metal sheet 1283 and the second innersurface 1289 of the second metal sheet 1287 are integrally bonded inareas other than the channel printed areas. Thereafter, in operation425, the auxiliary enhancement portion 1213 is formed by bending thecoupled first and second metal sheets 1283 and 1287. In someembodiments, the width W (FIG. 13B) of the auxiliary enhancement portion1213 is substantially equal to the separation between adjacent heatexchanger fins 1250. However, the embodiments are not limited thereto.The width may be shorter than the distance between adjacent heatexchanger fins 1250.

Those of ordinary skill in the relevant art will appreciate that the useof graphite serves as a release agent, thus, preventing the first andsecond metal sheets from integrally bonding in at least the areas of theapplied patterned. In other embodiments, other release agents may beused to prevent the first and second metal sheets from integrallybonding in the areas of the applied pattern.

In some embodiments, the thickness of the first and second metal sheetsis around 0.250 mm to around 3.00 mm, and the roll-bonding processreduces the thickness of the first and second metal sheets by around 40%to around 60%. However, in other embodiments, the thicknesses andreduction of the first and second metal sheets can be more or less,depending upon the material, original thickness, number of sheets,processes employed, and design requirements to obtain desired thermalperformance.

In some embodiments, the shape of each heat exchanger fin 1250 isquadrilateral shaped. However, embodiments are not limited thereto andthe heat exchanger fin may be of a shape other than quadrilateralshaped, and may be made up of more than one shape according toapplication and design requirements, and without departing from thescope of the disclosure.

FIG. 16A is schematic perspective view of the heat exchanger fin of FIG.12A and FIG. 12B following operation 440 of the manufacturing method1500 of FIG. 15 , according to embodiments of the disclosure. Referringto FIG. 16A, in operation 430 a working pipe 1217 is inserted andsecured to a working channel 1221, extending from the one end of aworking section 1257 of each heat exchanger fin 1250. The working pipe1217 allows for fluid communication with the condensation channel 1237,the auxiliary channels 1247, the connecting channels 1227, and theevaporation channel 1253. Following, in operation 440, the condensationchannel 1237, the auxiliary channels 1247, the connecting channels 1227,and the evaporation channel 1253 are inflated via a fluid (vapor or gas)having a pressure configured for even inflation throughout the heatexchanger fin 1250. In some embodiments, the gas is atmospheric airhaving a suitable pressure for inflation. However, embodiments are notlimited thereto, and in other embodiments, the gas or vapor may benitrogen, oxygen, argon, hydrogen, carbon dioxide, or any of thecommonly available commercial gasses or compatible mixtures thereof. Insome embodiments, the first and second metal sheets 1283, 1287 areinserted into a mold before inflating for even inflation throughout eachheat exchanger fin 1250.

In some embodiments, the cross-sectional width (or radius) of thecondensation channel 1237 and the evaporation channel 1253 is around0.125 mm to around 1.50 mm and of the auxiliary channels 1247 and theconnecting channels 1227 is around 0.0625 mm to around 0.75 mm. However,embodiments are not limited thereto and the widths can be increased ordecreased as required by application and design, without departing fromthe scope of the disclosure.

In operation 450, a working fluid is introduced into the inflatedchannels via the working pipe 1217 and then air is vacuumed out. FIG.16B is schematic perspective view of the heat exchanger fin 1250 of FIG.16A following operation 460 of the manufacturing method 1200 of FIG. 15, according to embodiments of the disclosure. Referring to FIG. 16B, inoperation 460, the working pipe 1217 is closed and sealed by flatteningand then sealing the first and second metal sheets 1285 and 1287, andafter cooling, the working channel of the working section 1257 istrimmed, thereby resulting in the heat exchanger fin 1250 including thecondensation channel 1237, the auxiliary channels 1247, the connectingchannels 1227, and the evaporation channel 1253.

FIG. 17 is a perspective view of a heat exchanger fin 1750, according toembodiments of the disclosure. The heat exchanger fin 1750 can beemployed in the heat exchanger 1200 of FIGS. 12A to 12B. The heatexchanger fin 1750 may be similar in some respects to the heat exchangerfin 1250 in FIGS. 12A to 16B, and therefore may be best understood withreference thereto where like numerals designate like components notdescribed again in detail. Referring to FIG. 17 , the auxiliaryenhancement portion 1213 further includes one or more auxiliary throughholes 1757. The auxiliary through holes 1757 are located in theauxiliary enhancement portion 1213 and separated by the auxiliarychannels 1247, and are separate (discrete) from the condensation channel1237 and the auxiliary channels 1247. However, in other embodiments, twoor more auxiliary through holes 1757 can be placed directly adjacenteach other and not separated by auxiliary channel(s) 1247.

The auxiliary through holes 1757 permit air to pass through portions ofthe auxiliary enhancement portion 1213, thereby further improving heatdissipation and thermal performance of each heat exchanger fin 1750 byallowing higher temperature air to more conveniently rise.

In some embodiments, a single auxiliary through hole 1757 can beincluded. The number of auxiliary through holes 1757 can be varied asrequired by design and application, without departing from the scope ofthe disclosure. In some embodiments, the auxiliary through hole 1757 iscircular-shaped. However, in other embodiments the auxiliary throughhole 1757 is quadrilateral-shaped, hexagonal-shaped, or any othersuitable shape that permits air to pass therethrough.

In some embodiments, the heat exchanger fin 1750 can be manufacturedusing the method 1500 discussed above, and the through-holes 1757 aredrilled between operation 440 and operation 450. The remainingoperations are similar and a discussion thereof is omitted for the sakeof brevity.

In some embodiments, the first metal sheet 1283 and the second metalsheet 1287 are made of aluminum, or an aluminum-alloy or the like, andformed by roll-bonding. In other embodiments, the first metal sheet 1283and the second metal sheet 1287 are formed by stamping or other desiredprocesses depending upon material and manufacturing requirements. Inother embodiments, the first metal sheet 1283 and the second metal sheet1287 include copper, or a copper-alloy or the like, or other malleablemetal heat conducting material having a relatively high thermalconductivity, depending upon application and design requirements.

In some embodiments, the base plate 1290 includes aluminum, or analuminum-alloy or the like and that can be utilized for brazingtechniques for thermal and mechanical brazing each fin base 1219 of theheat exchanger fin 1250 to the corresponding mounting grooves 1292. Inother embodiments, the base plate 1290 includes copper, or acopper-alloy or the like, or other malleable metal heat conductingmaterial having a relatively high thermal conductivity, depending uponapplication and design requirements.

In some embodiments, the base plate 1290 includes a solid malleablemetal heat conducting material having a relatively high thermalconductivity. In other embodiments, the base plate 1290 is under vacuumand has a working fluid therein. In yet other embodiments, the baseplate 1290 has an inlet and an outlet for introducing and removingworking fluid.

In some embodiments, if a stamping process or the like is used to formeach heat exchanger fin 1250, bonding methods, such as ultrasonicwelding, diffusion welding, laser welding and the like, can be used tobond and integrally form the first and second inner surfaces together atareas other than the channel areas.

In some embodiments, if a stamping process or the like is used,depending upon dimensions and application, axial or circumferential wickstructures, having triangular, rectangular, trapezoidal, reentrant, etc.cross-sectional geometries, may be formed on inner surfaces of thecondensation channel 1237, the auxiliary channel 147, the connectingchannel 1227, and the evaporation channel 1253. The wick structure isused to facilitate the flow of condensed fluid by capillary force backto the evaporation surface, keeping the evaporation surface wet forlarge heat fluxes.

Those of ordinary skill in the relevant art may readily appreciate thatin alternative embodiments, further heat treatment processes can beemployed throughout the manufacturing method of each heat exchanger fin1250, and the embodiments are not limited to those described.Additionally, those skilled in the relevant art may readily appreciatethat additional operations can be added to the process in order toincorporate additional features into the finished product. Also, theoperations can be altered depending upon different requirements. As anexample, the method 1500 can include operations of alloying, casting,scalping and pre-heating, intermediate operations such as intermediateannealing, and finishing operations such as solution heat treatment orfinal annealing, stretching, leveling, slitting, edge trimming andaging, and the like may be employed.

In further alternative embodiments, the heat exchanger fin 1250 and/or1750 can be employed as a stand-alone heat exchanger, without departingfrom the scope of the disclosure. In some embodiments, the working fluidincludes acetone. However, the embodiments are not limited thereto. Inother embodiments, the working fluid includes cyclopentane or n-hexane.

The foregoing outlines features of several embodiments or examples sothat those skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodiments orexamples introduced herein. Those skilled in the art should also realizethat such equivalent constructions do not depart from the spirit andscope of the present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A heat dissipation device, comprising: aplurality of parallel fins, wherein each of the fins comprises: a finbody including a first metal sheet and a second metal sheet coupled toeach other; a plurality of through holes formed through the fin body; aplurality of channels defined between the first and second metal sheets;and a working fluid in the plurality of channels, wherein the first andsecond metal sheets are recessed toward and bonded to each othersurrounding each of the through holes individually; and wherein eachthrough hole of the plurality of through holes is surrounded by theplurality of channels such that the through holes are separated from oneanother by the channels.
 2. The heat dissipation device of claim 1,wherein the first metal sheet and the second metal sheet are spacedapart from each other to define the plurality of channels.
 3. The heatdissipation device of claim 1, wherein the plurality of through holesare configured to cause air flowing therethrough to flow transverse toair flowing along surfaces of the first and second metal sheets.
 4. Theheat dissipation device of claim 1, wherein the plurality of throughholes have a staggered pitch.
 5. The heat dissipation device of claim 1,wherein a thickness of the first and second metal sheets is around 0.250mm to around 3.00 mm.
 6. The heat dissipation device of claim 1, whereinthe plurality of through holes have a same diameter.
 7. The heatdissipation device of claim 1, wherein the plurality of through holeshave different diameters.
 8. The heat dissipation device of claim 1,wherein the heat dissipation device is hemmed along an edge thereof. 9.A heat dissipation device, comprising: a base plate; and a plurality offins arranged on the base plate, wherein each of the fins comprises: afin body including a first metal sheet and a second metal sheet coupledto each other; a plurality of through holes formed through the fin body;a plurality of channels defined between the first metal sheet and thesecond metal sheet; and a working fluid in the plurality of channels,wherein the first and second metal sheets are recessed toward and bondedto each other surrounding each of the through holes individually; andwherein each through hole of the plurality of through holes issurrounded by the plurality of channels such that the through holes areseparated from one another by the channels.
 10. The heat dissipationdevice of claim 9, wherein the fins are arranged on the base plate in alongitudinally extending direction in which a longitudinal edge of eachfin contacts the base plate.
 11. The heat dissipation device of claim 9,wherein the base plate includes a plurality of grooves and each grooveincludes a corresponding fin of the plurality of fins.
 12. The heatdissipation device of claim 9, wherein the first metal sheet and thesecond metal sheet are spaced apart from each other to define theplurality of channels.